Neurology Specialty Labs
Available at ECCND
Nerve Conduction Study (NVC)
Nerve conduction studies are used mainly for evaluation of paresthesias (numbness, tingling, burning) and/or weakness of the
arms and legs. The type of study required is dependent in part by the symptoms presented. A physical exam and thorough history
also help to direct the investigation. Some of the common disorders which can be diagnosed by nerve conduction studies are:
Carpal tunnel syndrome
Facioscapulohumeral muscular dystrophy
Spinal disc herniation
An EMG is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMGs are performed
using an instrument called an electromyograph to produce a record called an electromyogram.
An electromyograph detects the electrical potential generated by muscle cells when these cells are electrically or neurologically
activated. The signals can be analyzed to detect medical abnormalities, activation level, recruitment order or to analyze the
biomechanics of human or animal movement. Source 1,2
An EEG is the recording of electrical activity along the scalp produced by the firing of neurons within the brain. In clinical
contexts, EEG refers to the recording of the brain's spontaneous electrical activity over a short period of time, usually 20–40
minutes, as recorded from multiple electrodes placed on the scalp.
In neurology, the main diagnostic application of EEG is in the case of epilepsy, as epileptic activity can create clear
abnormalities on a standard EEG study. A secondary clinical use of EEG is in the diagnosis of coma, encephalopathies and
brain death. EEG used to be a first-line method for the diagnosis of tumors, stroke and other focal brain disorders, but this use
has decreased with the advent of anatomical imaging techniques such as MRI and CT. Source 2,3
Polysomnography, also known as a sleep study, is a multi-parametric test used in the study of sleep and as a diagnostic tool in
sleep medicine. The test result is called a polysomnogram (PSG).
Polysomnography is a comprehensive recording of the biophysiological changes that occur during sleep. It is usually
performed at night, when most people sleep, though some labs can accommodate shift workers and people with circadian
rhythm sleep disorders and do the test at other times of day. The PSG monitors many body functions including brain (EEG),
eye movements (EOG), muscle activity or skeletal muscle activation (EMG) and heart rhythm (ECG) during sleep. After the
identification of the sleep disorder sleep apnea in the 1970s, the breathing functions respiratory airflow and respiratory effort
indicators were added along with peripheral pulse oximetry. Source
Neuro-cognitive testing can assist physicians when diagnosing and treating conditions related to memory and thinking. Our
medical team uses standardized computer-based testing to gather baseline (original) score and then monitor this score by
retesting the patient over certain intervals of time.
The test is helpful for patients with dementias—and even with athletes that play high-impact sports like football or soccer.
Autonomic Nervous System Testing (ANX 3.0)
The ANX 3.0 tests are two independent clinical tests designed to determine the ability of both branches of the autonomic
nervous system (ANS) to respond to and relax from a challenge. The two branches that make up the ANS are the sympathetic
and parasympathetic (SNS and PSNS, respectively).
The ANS is the part of your nervous system that functions to sustain your life by controlling your heart, lungs, digestive
system, blood pressure, immune system, certain reflexes, fluid balance, pupil diameter, sweating, and sexual function.
Visual Evoked Potential (VEP)
Visual evoked potential is a noninvasive study that measures the evoked responses to visual stimuli and assess the visual
conduction pathways through the optic nerves and brain. VEP allows a quantitative determination of visual function and is
highly sensitive to lesions of the optic nerve and anterior chiasm but relatively insensitive to ophthalmologic disorders.
Video-nystagmography (VNG) is a series of tests that are used to help determine the causes of a patient's dizziness or
balance problems. Dizziness can be caused by problems with the inner ear (the vestibule) or with the brain. Dizziness can
also be caused by medical disorders such as low blood pressure, or by psychological problems such as anxiety.
VNG is an advanced diagnostic system for recording and analyzing involuntary eye movements, called nystagmus, using
video imaging technology. Hi-tech video goggles with infrared cameras are worn throughout the test.
There are four main parts to the VNG. The saccade test evaluates rapid eye movements. The smooth pursuit test evaluates
movement of the eyes as they follow a visual target. The positional test records eye movements while the patient’s head and
body are positioned. The caloric test measures ocular responses to warm and cold air circulated through a soft, small tube in
the ear canal. The cameras record the eye movements and display them on a computer screen. This allows the examiner to
see how the eyes move which is very helpful in assessing balance system health.